Thymosin Alpha-1 is one of the most frequently referenced thymic peptides in immunology research. It has a well-documented origin, a short and fully characterised sequence, and a long publication history, which makes it a useful case study in what a research compound's documentation should look like. This is a reference on the peptide itself.
Where it came from
In the 1960s and 1970s, researchers working with extracts of calf thymus tissue separated a crude preparation known as thymosin fraction 5 into its individual polypeptides. One of them, named Thymosin Alpha-1, was isolated and fully sequenced in 1977 by Goldstein and colleagues and reported in the Proceedings of the National Academy of Sciences. That paper is still the starting reference for the compound.
Later work established that Thymosin Alpha-1 is not encoded as a standalone peptide. It is the N-terminal fragment of a larger precursor protein, prothymosin alpha, which is found in many tissues beyond the thymus.
The molecule
- Length: 28 amino acids.
- N-terminus: acetylated serine. The acetyl group is part of the native structure, and synthetic material should reproduce it.
- Molecular weight: approximately 3,108 Da.
- Character: strongly acidic, with a high proportion of glutamic and aspartic acid residues, and largely unstructured in water.
A synthetic version of the same sequence is approved as a medicine in a number of countries outside the United States under the name thymalfasin. Research-grade material is a separate product, supplied for laboratory work only.
What the research literature covers
Published work on Thymosin Alpha-1 spans several decades and focuses mainly on immune signalling in laboratory and preclinical models: T-cell maturation and differentiation, interactions with innate immune receptors, and cytokine signalling. Reviews of that literature are the best entry point for anyone designing a study, and the original isolation paper below is the reference for the sequence itself.
Reading its documentation
Because the sequence is short and well defined, Thymosin Alpha-1 is a good compound to practise reading a certificate of analysis on:
- Identity: the observed mass from mass spectrometry should sit close to the theoretical ~3,108 Da. A mass about 42 Da lower suggests the N-terminal acetyl group is missing.
- Purity: an HPLC figure with the method and conditions stated. How peptide purity is measured explains what that number means.
- Lot match: the lot number on the certificate should match the vial. See what a certificate of analysis shows.
Handling
Lyophilized Thymosin Alpha-1 is handled like other freeze-dried peptides: store sealed at -20°C, protected from light and moisture, and let the vial reach room temperature before opening. The full reference is how lyophilized peptides should be stored and shipped.
Reference
Goldstein AL, et al. Thymosin alpha1: isolation and sequence analysis of an immunologically active thymic polypeptide. Proceedings of the National Academy of Sciences USA, 1977;74(2):725–729.
Related
Browse Thymosin Alpha-1 or the full Antimicrobial & Host Defense Peptides collection.
For research use only. Not for human consumption. This article describes the published chemistry and history of a research compound and is not guidance for any human or veterinary use.
